Trimethyl ester of carboxydithioimido-carbonic acid

ABSTRACT

1. THE COMPOUND   CH3-S-C(-S-CH3)=N-COO-CH3

United States Patent Int. Cl. C07c 149/20 U.S. Cl. 260-481 C 1 ClaimABSTRACT OF THE DISCLOSURE Compounds of the formula:

RS (H) RiS where R, R and R are as defined hereinafter are useful aschemical intermediates. When reacted with o-phenylenediamines, they formZ-benzimidazolecarbamic acid alkyl esters, which compounds are useful asfungicides.

Exemplary of the compounds is methyl bis(methylthio)methyleneaminoformate.

CROSS REFERENCE TO RELATED APPLICATIONS This application is a divisionalof my copending application Ser. No. 681,102, filed Nov. 7, 1967, nowUS. Pat. 3,562,290.

BACKGROUND OF THE INVENTION BRIEF SUMMARY OF THE INVENTION Thisinvention relates to novel compounds of the following formula:

O=NC 0 R2 Ins wherein R and R can be the same or different and are alkylof 1 through 4 carbon atoms, alkenyl of 3 through 5 carbon atoms,cyclohexyl,

@ or Qua;

provided that R and R can be joined to form a ring containing 2 or 3methylene units;

X is, halo gen, methyl or nitro;

n is 0, 1 or 2, provided that when n is 1 or 2, the substituents do nothave to be identical;

R is methyl, ethyl, isopropyl or sec-butyl.

Patented Oct. 1, 1974 NR2 solvent NHz where R, R and R are as previouslydescribed; and where Z is alkyl of 1 through 5 carbon atoms, halogen,nitro or hydrogen.

DETAILED DESCRIPTION OF THE INVENTION The novel alkyl bis(alkyl orarylthio)methyleneaminoformates of the invention can be prepared by atwo-step sequence as indicated in the following equations:

Reaction 1 /C=NHH(ha1ogen) I R15 Reaction 2 RS RS Optionally, the firststep can be conducted in the manner illustrated by the followingequation:

Optional Reaction 1 where n is 2 or 3.

The reaction of mercaptans with thiocyanates or cyanogen halides as setforth in Reaction 1 is known in the art and is explained in greaterdetail in J. Org. Chem. 29, page 739 (1964). The teachings of thisreference are incorporated herein by reference.

The novel alkyl bis(alkyl or arylthio)methyleneaminoformates of theinvention are produced as illustrated in Reaction 2, when the product ofReaction 1 is reacted with a chloroformate in the presence of an acidacceptor.

The acid acceptor can be an organic or inorganic base such as sodiumhydroxide, sodium bicarbonate, or triethylamine in a polar or non-polarsolvent such as ether, benzene, dimethylformamide, acetone, cyclohexane,dioxane or water.

The conditions of Reaction 2 are not critical. Generally, the reactionwill be conducted with agitation at room temperature under atmosphericpressure. The time of the reaction also is not critical. The reactionwill be continued until the desired alkyl bis(alkyl orary1thio)methylaminoformate has formed; generally this will take from 30minutes to 5 hours.

After the reaction has been completed, the compounds can be isolated byconventional methods.

As previously set forth, the novel compounds of the invention can beused for the synthesis of Z-benzimidazolecarbamate acid, alkyl esters byreacting them with phenylenediamines in the presence of a suitablesolvent at temperatures from 25 to 150 C.

The reaction can also be run in the absence of a solvent; however, theuse of polar or non-polar solvents such as tetrahydrofuran, water-aceticacid, ethanol or dimethylformamide is preferred.

The concentrations of the starting materials in the reaction mixture areonly limited by the handling characteristics of the reaction mass.

During the course of the reaction, the reaction mixture should bestirred while the temperature is maintained between 25 to 150 C. Thetime of this reaction can range from 30 to 300 minutes. When thereaction is complete, the 2-benzimidazolecarbamate acid, alkyl esterproduct will be precipitated by cooling. The product is then isolated byconventional techniques such as filtration.

The invention will be more easily understood and practiced by referenceto the following illustrative examples. All parts are parts by weightunless otherwise indicated.

EXAMPLE 1 Synthesis of Methyl bis(methylthio)methyleneaminoformateSeventeen parts of solid sodium bicarbonate is added to a suspension of15.7 parts of dimethyl dithioiminocarbonate hydrochloride in cold C.)acetone (200 parts) which contains 9.5 parts of methyl chloroformate.The mixture is stirred for 30 minutes at 5 C., then for four hours atroom temperature.

The precipitate present is filtered and the filtrate is dried overmagnesium sulfate. Removal of the solvent gives 77 parts of methylbis(methylthio)methyleneaminoformate. This product is sufiiciently purefor reaction with o-phenylenediamine to form 2-benzimidazolecarbamicacid, ester.

A pure sample of the product is obtained by recrystallization fromchloroform-ether solvent, and it melts at 48 50 C. and gives thefollowing analysis: calculated for C5H9NO2S2.

Calculated: C, 33.45; H, 5.12; N, 7.88. Found: C, 33.50; H, 5.02; N,7.82.

EXAMPLE 2 Synthesis of 2-Benzimidazolecarbamic Acid, Methyl Ester Methylbis(methylthio)methyleneaminoformate (17.9 parts) is added to a solutionof parts of o-phenylenediamine in 200 parts of tetrahydrofuran. Themixture is refluxed for 3 hours, cooled and the precipitate present isfiltered. The identity of the isolated 2-benzimidazolecarbamic acid,methyl ester is established by comparison of the melting point andinfrared spectrum with those of an authentic sample.

EXAMPLE 3 One-Step Synthesis of 2-Benzimidazolecarbamic Acid, MethylEster A solution of 10% sodium hydroxide is added drop wise to a cold(512 C.) stirred solution of 39.4 parts of dimethyl dithioiminocarbonatehydrochloride and 25 parts of methyl chloroformate in 100 parts ofwater.

When the pH of the medium reaches 7.5, the addition of sodium hydroxideis stopped and a slurry of o-phenylenediamine (21.6 parts) in 10 partsof glacial acid is added. The reaction mixture is stirred and refluxedfor 75 minutes, cooled and the solid present is filtered. The solid iswashed with a small amount of alcohol to give 13 parts of the subjectcompound. The identity of the product is confirmed by infrared spectralcomparisons.

EXAMPLES 4-13 The following intermediates are prepared in the manner ofmethyl bis(methylthio)methyleneaminoformate of Example 1 by substitutingequivalent amounts for the dimethyl dithioiminocarbonate hydrochlorideand methyl chloroformate used in Example 1.

Starting materials Product 4, Butyl methyl dithloiminosec-Buty1[(butylthi0) (in ethylcarbonate hydrochloride plusthio)methyleneamino] sec-butyl chloroformate. formate. 5. Allylcyclohexyl dithioimino- Isopropyl[(allylthio) (cycloearbonatehydrochloride plus hexylthio)methyleneamino]- iso propyl chloroformate.

6 3,4-dichlorobenzyl methyl dithioiminocarbonate hydrochloride plusmethyl chloroform ate. Methyl[(3,4-dichlorbenzylthio)(methylthio)methyleneaminoh'ormate.

Ethyl[(methylthio) (phenylthio)methyleneamino]- formate.Ethyl[(trimethylene dithio) methyleneaminohormate.

Methyl bis(butylthio)methyleneimlnoiormate.

Isopropyl[(methylthio) (4- nitrophenylthio)methyleneamino1forrnate.

Methyl bis(phenylthio)methyleneaminoiormate.

Methyl[(allylthio) (4chlorophenylthio)methyleneaminohormate.

Ethyl[(2-ehloro-4-tolylthio) (methylthio)rnethyleneamino1lormate.

EXAMPLES 14-16 Heating o-phenylenediamine and an alkyl 'bis(alkyl orarylthio)methyleneaminoformate in a polar or a nonpolar solvent gives2-benzimidazolecarbamic acid, alkyl esters as in Examples 2 and 3. Thefollowing examples are illustrative of this process:

Starting materials Product 14- sec-B utyl [(butylthio)-(metl1ylthio)methyleneamino] formate plus o-phenylenediaminc.

15..--.- Isopropyl [(allythio)-(eyclohexylthio)methyleneamino] formateplus o-phenylenediaminc. 16. Ethyl [(methylthio) (phenyl- 'o)methyleneamino]- lormate plus o-phenylenediaminc.

Z-benzirm'dazolecarbamic acid,

sec-butyl ester.

2-benzimidazolecarbamic acid, isopropyl ester.

Z-benzimidazoleearbamlc acid, ethyl ester.

EXAMPLES 17-25 The following 2-benzimidazolecarbamic iacid, alkyl esterscan be prepared from the reactants given below according to the methodsdescribed in Examples 2 and 3.

Reactants Product 17. 4-butyl-l,Z-phenylenediamine6-butyl-2-henzimidazoleand methyl bis(methylthio)- carbamic acid,methylester. methylcneaminolormate.

18- 4-mcthyl-l,Z-phenylenediamine E-methyI-Z-benmmidazoleand methylbis(methylthio) carbamic acid, methyl ester. methyleneaminolormate.

19- 4-chloro-1,Z-phenylenediamine 5-ehlor0-2-benzimidazolcand methylbis(methylthio)- carbamic acid, methyl ester. methyleneaminoiormate.

20 4-br0mo-l,2-phenylenediamine fi-bromo-Z-benzimidazoleand methylbis(methylthio)- oarbamic acid, methyl ester. methyleneaminoformate.

21. 4-nitr0-1,2-phenylenediamine E-nitro-Z-benzrmidazoleand methylbis(methylthio)- oarbamic acid, methyl ester. methyleneaminoformate. I

22- 4-Iluoro-1,Z-phcnylenediarnine 5-flu0ro-2-benz1m1dazo1eand methylbis(methylthio)- carbamic acid, methyl ester. methyleneaminoformate.

23- 4-iodo-l,Z-phenylenediamine 5-iodo-2-benzimidazoleand methylbis(methylthio) carbamic acid, methyl ester. methyleneaminoformate.

24- 3-chloro l,Z-phenylenediamine 4-ehl0ro-2-benz 1m1daz0lcand sec-butylbis(methylearbamic acid, sec-butyl thio)-methyleneamiuoester. formate.

25- 3-brom0-l,Z-phenylenediamine 4-bromo-2-benzimidazoleand ethylbis(methylthio)- carbamic acid, ethyl ester. methyleueaminoformate.

I claim: 5 FOREIGN6 PATENTS The compound 1,135,583 4/1968 England.

L OTHER REFERENCES 5 Chemical Abstracts, vol. 59 (1964), p. 8554 old.0333 Burger: Medicinal Chem, p. 75, RS403B8.

References Cited Timmons et al.: J. Org. Chem. 32, 1566 (1967).

UNITED STATES PATENTS LORRAINE A. WEINBERGER, Primary Examiner 2,651,6589/1953 B l 260-471 10 J. F. TERAPANE, Assistant Examiner 3,755,3638/1973 Timmons et a1. 260-327 M 3,652,256 3/1972 DAmico 71-90

1. THE COMPOUND